This invention relates to microstrip antennas and more particularly to a multi-mode antenna using both microstrip antenna elements and a backfire cavity.
Compact missile-borne antenna systems require complex antenna beam shapes. At times, these beam shapes are too complex to obtain with a single antenna type, such as slots, monopoles, microstrip, etc., and require a more expensive phased array.
A less expensive approach can be realized in a multi-mode antenna incorporating two or more antenna types into one single new antenna configuration, and using the radiation pattern of each antenna type to provide a desired new and unique combined radiation pattern. This requires techniques for exciting two or more antenna modes with one single input feed and also for controlling the excitation of the mode of each antenna type in order to better shape the pattern.